The present invention relates to turbomachines and, more particularly, to an upstream rotor of such turbomachines.
Although the present invention is particularly well suited to aircraft turbine engines, it is not, however, restricted to that aeronautical application.
In a known way, a turbine engine comprises a gas generator formed of one or more sets of rotors rotating about a common axis. Each set, known as a spool, is made up of a compressor and of a turbine which are connected by a shaft or a drum and positioned one upstream of and the other downstream of a combustion chamber in relation to the flow of gas streams through the turbine engine. Associated with this gas generator is a fan that it drives. When the fan rotor is positioned at the front of the turbine engine, the air inlet of the generator is situated downstream of this rotor.
Moreover, it is known that the fan rotor comprises a spinner which forms the most upstream rotating part of the turbine engine. Through its shape, the spinner improves the aerodynamics of the turbine engine and, through a centrifugal effect, allows most foreign bodies entering the turbine engine to be deflected into a secondary stream.
It is also known that the spinner of a turbine engine is generally attached to the fan rotor by axial clamping, this being obtained by connecting a clamping plate secured to the spinner to a clamping plate connected to the rotor using a set of screws oriented along the longitudinal axis of the turbine engine. Each screw head requires the formation of a flat surface, using a spot-facing operation, allowing it to bear against the body of the spinner and be recessed therein in order to limit aerodynamic losses.
However, despite these precautions, the screw head and the spot faces made in the spinner are still “visible” to the incoming air stream. Further, because of the axial orientation of the screws (i.e. because they are oriented in the same direction as the incoming air stream), the frontal surface of the screws visible to the air stream is at a maximum, encouraging aerodynamic losses and increasing the drag of the turbine engine and, therefore, the fuel consumption thereof.
Moreover, recourse to a plurality of screws for axially clamping the spinner to the fan rotor means that it takes a great deal of time to fit and to remove the spinner. Now, because the spinner is the first removable component on the upstream part of the fan rotor, it is frequently required to be removed.
What is more, the use of screws for axially clamping the spinner entails recourse to tooling capable of measuring with precision the tightening torque applied, so as to prevent any damage to the fastening. The use of this special-purpose tooling increases the time that the operations take and, therefore, increases aircraft maintenance costs.